Georgina Sparks

Georgina is Serena's evil former friend who returns to New York City after escaping rehab in Utah. (Her parents had forced her into rehab after she dropped out of an equestrian circuit and sold her show pony for cocaine. Yeah, she's trouble.) Her sudden return is not welcomed by the UES clique. At first, Georgina is determined to ruin Serena's life. She blackmails Serena with a bit of scandalous info from her party-girl past, and if that weren't bad enough, she also attempts to seduce Dan. Once she's found out and foiled, Georgina is sent to reform school—thanks to Blair. She reappears in Season 2 when Chuck and Blair go to collect her from the church camp that was her punishment. They need her to help them formulate a plot against Gabriel and Poppy Lifton. Georgina claims to be reformed and high on Jesus, but Blair unwittingly jolts her out of that brief flirtation with Christianity. At the end of the season, Georgina requests Blair as her roommate at NYU. She's always got something up her sleeve…